Anti-reflection optical member

Abstract

An anti-reflection optical member has a laminated structure including: a transparent substrate having a first refractive index greater than that of a predetermined medium; a metal-microparticle-containing layer containing metal microparticles; and a dielectric layer having a second refractive index greater than that of the predetermined medium, in this order. At least 60% of the metal microparticles are flat particles with a diameter-to-thickness ratio of 3 or more. Principal planes of the flat metal particles are surface-oriented in the range from 0° to 30° relative to the surface of the metal-microparticle-containing layer. In the metal-microparticle-containing layer, the metal microparticles are disposed without forming a conductive path. The dielectric layer has such a thickness that light reflected at the surface of the dielectric layer of incident light entering the laminated structure from the surface is interfered and canceled by light reflected at the interface between the dielectric layer and the metal-microparticle-containing layer.

What is claimed is: 
     
       1. An anti-reflection optical member, used in a medium, that prevents incident light with a predetermined wavelength from being reflected, the anti-reflection optical member comprising a laminated structure in which the following are laminated in this order:
 a transparent substrate that has a first refractive index greater than that of the medium; 
 a metal-microparticle-containing layer that contains a plurality of metal microparticles; and 
 a dielectric layer that has a second refractive index greater than that of the medium, 
 wherein at least 60% of all the plurality of metal microparticles are flat metal particles each of which has a ratio of diameter to thickness of equal to or greater than 3, 
 wherein main flat surfaces of the flat metal particles are oriented in a plane at in a range of 0° to 30° to a surface of the metal-microparticle-containing layer, 
 wherein in the metal-microparticle-containing layer, the plurality of metal microparticles is disposed without forming a conductive path, 
 wherein a thickness of the dielectric layer is a thickness at which light reflected on a surface of the dielectric layer in a case where the incident light enters the laminated structure from the surface of the dielectric layer interferes with and is canceled out by light reflected on an interface between the dielectric layer and the metal-microparticle-containing layer, 
 wherein said incident light with the predetermined wavelength is visible light, and 
 wherein a wavelength bandwidth, at which a reflectance of the incident light is equal to or less than 0.5%, is equal to or greater than 100 nm. 
 
     
     
       2. The anti-reflection optical member according to  claim 1 , wherein the predetermined wavelength is a wavelength shorter than a plasmon resonance wavelength of the flat metal particles. 
     
     
       3. The anti-reflection optical member according to  claim 2 , wherein a thickness of the dielectric layer is equal to or less than 400 nm. 
     
     
       4. The anti-reflection optical member according to  claim 3 , wherein the thickness of the dielectric layer is a thickness which is equal to or less than an optical path length of λ/4 when the predetermined wavelength is set as λ. 
     
     
       5. The anti-reflection optical member according to  claim 2 , wherein the thickness of the dielectric layer is a thickness which is equal to or less than an optical path length of λ/4 when the predetermined wavelength is set as λ. 
     
     
       6. The anti-reflection optical member according to  claim 1 , wherein a thickness of the dielectric layer is equal to or less than 400 nm. 
     
     
       7. The anti-reflection optical member according to  claim 3 , wherein the thickness of the dielectric layer is a thickness which is equal to or less than an optical path length of λ/4 when the predetermined wavelength is set as λ. 
     
     
       8. The anti-reflection optical member according to  claim 1 , wherein the thickness of the dielectric layer is a thickness which is equal to or less than an optical path length of λ/4 when the predetermined wavelength is set as λ. 
     
     
       9. The anti-reflection optical member according to  claim 1 , wherein the flat metal particles have a diameter that is equal to or less than 300 nm. 
     
     
       10. The anti-reflection optical member according to  claim 1 , wherein the metal microparticles are made of silver. 
     
     
       11. The anti-reflection optical member according to  claim 1 , wherein the first refractive index is less than 1.8. 
     
     
       12. The anti-reflection optical member according to  claim 1 , wherein in the metal-microparticle-containing layer, at least 50% of the plurality of metal microparticles are disposed to be isolated from each other. 
     
     
       13. The anti-reflection optical member according to  claim 1 , comprising a high-refractive index layer that has a third refractive index greater than the first refractive index between the transparent substrate and the metal-microparticle-containing layer. 
     
     
       14. The anti-reflection optical member according to  claim 1 , wherein an area ratio between the plurality of metal microparticles and the metal-microparticle-containing layer in plan view is equal to or greater than 5% and equal to or less than 70%. 
     
     
       15. The anti-reflection optical member according to  claim 1 , wherein a transmittance of the incident light is equal to or greater than 80%.